1. Field of the Invention
The present invention relates to a gate break device of a lead frame already sealed with resin, and a gate break method, and more particularly to a gate break device and a gate break method capable of shorten time required for gate break.
2. Description of the Background Art
In resin seal forming of lead frame, unnecessary parts such as cull, runner and gate are formed inevitably. It is the gate break device that is intended to remove such parts.
FIG. 10 shows a constitution of a conventional gate break device. In FIG. 10, a resin-sealed lead frame 1 which are sealed and formed with resin is put on a break table 2. The resin-sealed lead frame 1 has unnecessary parts such as cull 13, runner 14, and gate 15, aside from a frame 12 comprising a semiconductor package 11, and the cull 13 is fixed between a cull cradle 21 and a cull holder 22. The resin-sealed lead frame 1 is restricted in position by plural positioning pins 23 provided vertically on the break table 2.
The break table 2 is put on a base table 24, and a break unit 3 is mounted on the break table 2.
The break unit 3 has plural break pins 31 disposed corresponding to the specified positions of the resin sealed lead frame 1, and the break pins 31 are fixed by a break pin mounting plate 32 and a break pin holding plate 33. The break pins 31 are designed so as to be longer at a position further from the cull 13.
Herein, the specified positions of the resin sealed lead frame 1 are break regions BP provided beforehand in the frame 12 for removing the cull 13. runner 14, and gate 15, generating indicating the upper part of the runner 14 near the gate 15, and an opening wider than the pin diameter of the break pin 31 is beforehand formed in the frame 12 of the corresponding part. By a step of resin seal forming, this opening is filled up with the resin, but as seen from the break pin 31 side, it is recognized as the exposed region of resin surface in a shape of the opening in the surface of the frame 12.
Referring now to FIG. 10 and FIG. 11, the operation is described below. First, the resin-sealed lead frame 1 is transported from a resin sealing device which is not shown by a transporting device which is not shown, and is put on the break table 2, and at this time, by inserting a positioning pin 23 into a positioning hole preliminarily formed in the frame 12 of the resin-sealed lead frame 1, the position of the resin-sealed lead frame 1 is restricted.
Once the position of the lead frame 1 is determined, the cull 13 is positioned above the cull cradle 21, and the cull holder 22 descends, and the cull 13 is held and fixed by the cull cradle 21 and cull holder 22.
When fixing of the cull 13 is over, the break unit 3 begins to descend, and the break pin 31 at the remotest position from the cull 13 reaches the break region BP of the frame 12, and as it descends further, other break pins 31 sequentially reach the break region BP to push down the resin surface exposed on the surface of the frame 12, thereby peeling the gate 15 from the frame 12 and also peeling the runner 14.
After the gate 15 and runner 14 are peeled, when the break pins 31 are further lowered, since the cull 13 is fixed, the runner 14 is broken at the boundary of the runner 14 and cull 13, so that the gate 15 and frame 12 are separated from the lead frame 1.
Herein, the state after separation of the gate 15 and runner 14 is shown in FIG. 11. Notches are formed in the break table 2 and base table 24 in which the separated gate 15 and runner 14 drop, and the separated gate 15 and runner 14 are automatically put into a container which is not shown through the inside of the break table 2 and table base 24. On the other hand, the cull 3 is left over as being fixed by the cull cradle 21 and cull holder 22, and the semiconductor package 11 and frame 12 are left over on the break table 2.
The conventional gate break device is thus composed, and to mount the resin-sealed lead frame 1 on the break table 2, it was necessary to move the resin-sealed lead frame 1 to above the break table 2 by using a transporting device from the resin sealing device, and lower the resin-sealed lead frame 1 so as to insert the positioning pin 23 into the positioning hole provided preliminarily in the frame 12.
Therefore, aside from the break unit 3, a transporting device for transporting the resin-sealed lead frame 1 was needed. Herein, the configuration of the positioning pin 23 and positioning hole is strictly defined, and if the resin-sealed lead frame 1 is deviated when taking out from the resin sealing device or in the midst of transporting, the positioning pin 23 cannot be inserted into the positioning hole, and a high precision is required in the transporting device and the structure is complicated, the equipment cost increases, it takes a longer time in positioning the resin-sealed lead frame 1, and also a long time is needed in gate break.
The separated gate 15 and runner 14 are automatically put in the container by passing through the inside of the break table 2 and base table 24, but the cull 13 is left over on the cull cradle 21, and to process a next resin-sealed lead frame 1, a step and a mechanism for eliminating the cull 13 are needed, which adds to the cost of the equipment.